Rigid ballistic composites made from poly-para-phenylene terephthalamide fibers having large denier per filament

ABSTRACT

According to some embodiments, there is provided a ballistic-resistant composite including a plurality of large denier per filament (dpf) yarns. The large dpf yarns may have a “Composite-Armor dpf factor” (CA•dpf) of greater than or equal to 6.9.

RELATED APPLICATIONS

This application claims the benefit of U.S. Provisional PatentApplication No. 61/170,820, filed Apr. 20, 2009 and entitled “ImprovedBallistic Composites Having Large Denier Per Filament High PerformanceYarns”, the entire contents of which are incorporated herein byreference for all purposes.

TECHNICAL FIELD

The embodiments disclosed herein relate to ballistic-resistantcomposites, and in particular to ballistic-resistant composites that usefibers or filaments with large denier per filament (dpf) ratios.

INTRODUCTION

There is currently a great demand for rigid or semi-rigid compositearmor systems that are lightweight, inexpensive and offer improvementsin ballistic performance. To meet this demand composite armor systemsutilizing high performance yarns, such as aramids (e.g. Kevlar®,Twaron®, Heracron®), UHMWPE (e.g. Spectra®, Dyneema™) HMPP (e.g.Innegra™), polypropylene, polyester, Nylon, PBO, Vectran®, S-2 Glass®,Basalt, M5 fiber, carbon, etc., are increasingly being used incombination with thermoplastic and thermoset resin systems.

Traditionally, better ballistic performance, particularly in soft armorouter-tactical vests, has been achieved through the use of finer orsmaller dtex yarns and finer or smaller denier per filament (dpf) yarns,which have been found to be efficient in dissipating the energy from ahigh-speed ballistic projectile. In addition, ballistic performanceimprovements have been achieved through the use of high performanceyarns that have been specifically engineered to have higher tensilestrength, higher initial modulus, and/or increased % elongation tobreak. However, these solutions typically result in a more expensiveinput yarn and hence significantly more expensive armor products.

Relatively little work has been done in the field of correlating dpf andballistic performance in rigid armor due to a number of factors: a) itis typically very costly and complicated to produce identical denieryarns at different dpfs for experimental testing, b) the number offilaments and dpf of many ballistic yarns are also often keptconfidential by the companies producing the yarns, and c) historically,armor manufacturers have had limited knowledge of textiles and howhigh-performance yarns are made.

Park et al (US 2008/0006145) discloses a hard armor composite thatincludes a rigid facing and a ballistic fabric backing. Park disclosesthe use of low dpf fibers including Twaron® of 1.5 dpf and lower,Spectra Shield® PCR of less than 5.4 dpf, Dyneema® Unidirectional (UD)fiber of less than 2.0 dpf, PBO Zylon® of 1.5 dpf or lower, and aramidKevlar® of 1.5 dpf. The preferred embodiments taught by Park useshigh-performance fibers having less than 5.4 dpf, more preferably, lessthan 2.0 dpf, and most preferably, less than 1.5 dpf.

SUMMARY

Embodiments described herein relate generally to the use of large dpffibers or filaments in rigid or semi-rigid ballistic-resistantcomposites. According to one aspect, there is provided aballistic-resistant composite comprising organic high-performance fibersand a resin or laminate, such as a thermoplastic ballistic film.

In some embodiments, the ballistic-resistant composites as describedherein may also be useful as blast-resistant composites.

Generally, some embodiments include a ballistic resistant compositehaving an organic high-performance fiber or filament and exhibit greaterballistic performance with increasing dpf of the fiber or filament.

The ballistic-resistant composites disclosed herein are believed to haveat least some of the following advantages:

-   -   Provide comparatively lower priced armor systems through the use        of lower cost input yarn to produce the composite armor.    -   Provide equivalent weight ballistic panels, helmets, armor, or        other composite members, etc. with improved ballistic        performance (i.e. armor with a higher V₅₀ performance than a        comparable weight armor made from smaller dpf yarn).    -   Provide lighter weight ballistic panels, helmets, armor or other        member, etc. with the same ballistic V₅₀ performance as heavier        armor systems.    -   Provide new ballistic markets and applications for large dpf        high performance yarns.    -   Provide better performing ceramic armor backing systems (e.g.        weight/cost/performance) than currently available systems.    -   Make effective use of lower cost, organic high performance        synthetic yarns (HMPP, Nylon, PET, PP, etc.) in composite rigid        or semi-rigid armor systems produced with large dpf yarn.

According to one aspect there is provided a ballistic-resistantcomposite comprising a plurality of large denier per filament (dpf)yarns. The large dpf yarns may have a “Composite-Armor dpf factor”(CA•dpf) selected to provide improved ballistic performance, whereinCA•dpf is determined according to the following equation:

${{CA} \cdot {dpf}_{factor}} = {\frac{{dpf}_{yarn}}{\left( \frac{1}{\left( {density}_{yarn} \right)^{3}} \right)} = {{dpf}_{yarn} \times \left( {density}_{yarn} \right)^{3}}}$

The large dpf yarns may have a CA•dpf greater than or equal to 6.9.

The large dpf yarns may include aramid fibers having a CA•dpf of greaterthan 6.72. The large dpf yarns may include modified para-aramid fibershaving a CA•dpf of greater than 3.49. The large dpf yarns may includepolyester polyarylate fibers having a CA•dpf of greater than 6.86. Thelarge dpf yarns may include HMPP fibers having a CA•dpf of greater than4.74 based on measured density of the yarns. The large dpf yarns mayinclude HMPP fibers having a CA•dpf of greater than 6.03. The large dpfyarns may include UHMWPE fibers having a CA•dpf of greater than 4.93.The large dpf yarns may include include PBO fibers having a CA•dpf ofgreater than 5.7. The large dpf yarns may include include M5 fibershaving a CA•dpf of greater than 4.91. The large dpf yarns may includeinclude carbon fibers having a CA•dpf of greater than 3.27. The largedpf yarns may include include polylolefin fibers having a CA•dpf ofgreater than 4.95.

The large dpf yarns may have a CA•dpf between 6.9 and 16. The large dpfyarns may have a CA•dpf between 16 and 42. The large dpf yarns may havea CA•dpf of less than 85.

The large dpf yarns may comprise aramid fibers having a dpf greater than2.25. The large dpf yarns may comprise aramid fibers having a dpfbetween 2.25 and 9.5.

The large dpf yarns may comprise modified para-aramid fibers with a dpfgreater than 1.1. The modified para-aramid fibers may have a dpf ofbetween 1.1 and 8.8.

The large dpf yarns may comprise UHMWPE fibers with a dpf greater than5.4. The UHMWPE fibers may have a dpf between 5.4 and 30.6.

The large dpf yarns may comprise polyester polyarylate fibers with a dpfof greater than 2.5. The polyester polyarylate fibers may have a dpfbetween 2.5 and 35.

The large dpf yarns may comprise high-performance fibers made fromaliphatic (non-aromatic) polyolefins, and have a dpf of greater than2.5. The aliphatic polyolefin fibers may include high moduluspolypropylene fibers having a dpf greater than 8. The aliphatic highmodulus polypropylene polyolefin fibers may have a dpf between 8 and 50.

The ballistic-resistant composite may further comprise a resin incontact with the plurality of large dpf yarns. The resin may be athermosetting resin. The resin may be a thermoplastic resin. The resinmay be selected from the group consisting of: polyesters;polypropylenes; polyurethanes; polyethers; polybutadiene; polyacrylate;copolymers of ethylene; polycarbonates; ionomers; ethylene acrylic acid(EAA) copolymers; phenolics; vinyl esters; PVB phenolics; naturalrubbers; synthetic rubbers; polyethylene; and styrene-butadiene rubbers.

The plurality of large dpf yarns may include organic high-performancefibers. The plurality of large dpf yarns may include industrial fibers.

According to another aspect, there is provided a composite armor membercomprising: at least one fabric layer; and a resin for securing the atleast one fabric layer together; wherein the at least one fabric layercomprises a plurality of large dpf yarns.

According to yet another aspect there is provided a protective materialcomprising a ballistic-resistant composite that includes a plurality oflarge dpf fibers. The protective material may be one of: body armor;personal armor plates; personal armor shields; commercial vehicle armor;military vehicle armor; lightweight aircraft armor; ship armor; helmets;and structural armor.

BRIEF DESCRIPTION OF THE DRAWINGS

The drawings included herewith are for illustrating various examples ofarticles, methods, and apparatuses of the present specification and arenot intended to limit the scope of what is taught in any way. In thedrawings:

FIG. 1 is a comparison of ballistic-resistant composites made with 5.0dpf versus 2.5 dpf Vectran® HT;

FIG. 2 is a comparison of ballistic-resistant soft-armor made with 1.5dpf vs. 2.25 dpf Kevlar®;

FIG. 3 is a comparison of ballistic-resistant composites made with 1.5dpf vs. 2.25 dpf Kevlar®;

FIG. 4 is a comparison of ballistic-resistant composites made with 8.0dpf vs. 12.5 dpf HMPP (Innegra™);

FIG. 4A is a comparison of ballistic-resistant composites made with 8.0dpf, 12.5 dpf and 19.0 dpf HMPP (Innegra™);

FIG. 5 is a comparison of ballistic-resistant composites made with 5.0dpf vs. 15.0 dpf Vectran®;

FIG. 6 is a curve of the theoretical performance of ballistic-resistantVectran® composites at different dpf using a polymomial model; and

FIG. 7 is a curve of the theoretical performance of ballistic-resistantVectran® composites at different dpf using a logarithmic model.

DETAILED DESCRIPTION

Exemplary embodiments described herein include ballistic-resistant rigidor semi-rigid composites made with high-performance fibers whereincreasing the dpf of the high-performance fibers improves the ballisticperformance of the composite.

The inventor has surprisingly discovered that the ballistic performanceof rigid or semi-rigid composites tends to improve with the use oflarger dpf fibers or filaments.

The ballistic-resistant composites described herein tend to beparticularly effective in composite armors where improved ballisticperformance is desired at equivalent or lower raw material input costs.Some embodiments described herein include woven, unidirectional, and/ornon-woven fabric/fiber matrices, and/or three-dimensional fibersmatrices, consolidated into a ballistic resistant composite armor (i.e.helmets, commercial vehicle armor panels, military vehicle armor, suchas spall liners, fragmentation kits, IED protection, EFP protection,lightweight aircraft armor, small arms protective inserts, protectivearmor for structures (e.g. buildings, military tents, etc.), armorshields, blast resistant barriers, etc.)

Fiber or Yarn Types

As used herein, the terms “fiber” or “filament” refer to an elongatedbody for which the length dimension is greater than the transverse orwidth dimension. In some embodiments, a plurality of fibers running inthe same generally longitudinal direction may constitute a yarn.

As used herein, the term “denier per filament (dpf)” refers to thelinear mass density of a filament expressed as the mass in grams per9000 meters of filament.

In one aspect, the ballistic-resistant composites described herein aremade from organic fibers or filaments that are known in the art ofballistic-resistant composites.

In some embodiments, the fibers are high-performance fibers such asaramid fibers, extended chain polyethylene fibers, and/orpoly(p-phenylene-2,6-benzobisoxazole) (PBO) fibers. Other examples couldinclude aramid and copolymer aramid fibers, for example as producedcommercially by DuPont (Kevlar®), Teijin (Twaron®), Kolon (Heracron®),and Hyosung Aramid, aromatic heterocyclic co-polyamides also referred toherein as modified para-aramids (e.g. Rusar®, Autex®), ultra highmolecular weight polyethylene (UHMWPE) produced commercially byHoneywell, DSM, and Mitsui under the trade names Spectra®, Dyneema®, andTekmilon®, respectively (as well as Pegasus® yarn),poly(p-phenylene-2,6-benzobisoxa-zole) (PBO) (produced by Toyobo underthe commercial name Zylon®), and/or polyester-polyarylate yarns (e.g.Liquid crystal polymers produced by Kuraray under the trade nameVectran®). In some embodiments, industrial fibers such as Nylon,polyester, polyolefin based yarns (including polyethylene andpolypropylene), could also be used in ballistic fabrics.

In some embodiments, the ballistic-resistant composites include organichigh-performance fibers made from an aromatic polyester (e.g.polyester-polyarylate) with a dpf of between 1.5 and 5. In otherembodiments, the fibers may be aromatic polyester with a dpf of greaterthan 2.5. In other embodiment, the aromatic polyester fibers may have adpf greater than 5. In further embodiments the aromatic polyester fibersmay have a dpf between 5 and 8, between 8 and 12, between 12 and 20, orhave a dpf greater than 20. In some embodiments, the high-performancearomatic polyester fibers may include Vectran™ fibers.

In other embodiments, the ballistic-resistant composite includeshigh-performance fibers made from an aromatic polyamide (e.g. aramid)and have a dpf between 1 and 2.25. In other embodiments, the aramidfibers may have a dpf greater than 2.25. In further embodiments, thearamid fibers may have a dpf between 2.25 and 5, between 5 and 8,between 8 and 12, between 12 and 20, or have a dpf greater than 20. Insome embodiments the high-performance aromatic polyamide fibers mayinclude Kevlar™ fibers.

In some embodiments, the ballistic-resistant composite includeshigh-performance fibers made from aliphatic (non-aromatic) low densitypolyolefins, such as ultra high-molecular weight polyethylene (UHMWPE),polypropylene, and synthetic fibers such as PET or Nylon/Amides, andhave a dpf between 2.0 and 12.5. In some embodiments, the aliphatic lowdensity polyolefin fibers may have a dpf greater than 8. In otherembodiments, the aliphatic low density polyolefin fibers may have a dpfgreater than 11. In further embodiments, the aliphatic low densitypolyolefins fibers may have a dpf greater than 12.5. In furtherembodiments, the aliphatic low density polyolefins fibers may have a dpfbetween 12.5 and 15, between 15 and 20, have a dpf greater than 20, havea dpf greater than 60, or between 60 and 100. In one embodiment thealiphatic low density polyolefins fibers may be made from Innegra™ SHMPP.

In some embodiments, the fibers may be modified para aramid (e.g. AuTexHT) with a dpf greater than 1.1. In other embodiments, the fibers may bemodified para-aramid with a dpf between 1.1 and 2.2. In yet otherembodiments, the fibers may be a modified para-aramid having a dpfgreater than 2.2.

In some embodiments, the fibers may be UHMWPE (e.g. Spectra™ Dyneema™)with a dpf above 5.4. In other embodiments, the fibers may be UHMWPEwith a dpf between 5.4 and 7.6. In yet other embodiments, the fibers maybe UHMWPE with a dpf greater than 7.6.

The embodiments described herein generally do not use or substantiallyinclude fibers or yarns made from inorganic yarns, such as basalt orglass fibers. For example, ballistic composites made using small dpf S-2glass fibers generally show better ballistic performance as compared toequivalent composites made using larger dpf S-2 glass fibers, and thusare generally not suitable for the embodiments as described herein.

Base Fabrics

According to some embodiments, the ballistic-resistant compositesdescribed herein may include fibers or yarns that are arranged into afabric. As used herein, the term “fabric” refers to a plurality offibers that have been arranged so as to form a generally continuoussheet and may include woven, unidirectional, and/or non-wovenfabric/fiber matrices made using the organic fibers or filaments asdescribed herein.

It will be understood that in some embodiments a particular fabric maybe made from a single type of fiber, or from two or more various typesof fibers. The fabric may also include various types of fibers in eachyarn and/or in different yarns that are combined to make the fabric.

In some embodiments, the fabric may be woven on standard weaving looms,including rapier, shuttle, air jet, projectile and water jet looms, oron more complex weaving machines, such as three-dimensional to createmulti-layer or three dimensional fabrics or weaving machines that allowcross-axial insertion.

In some embodiments the fabric is woven. However, the fabric can also beknitted or a non-woven structure. Woven fabrics may include any weavesuch as a plain weave, crowfoot weave, basket weave, satin weave, twillweave, proprietary weaves, or the like. The fabric may also be plied,that is, consisting of one or more layers attached together using anadhesive, thermal adhesive, stitching, matrix, or any other method knownfor combining layers of fabric.

Non-woven fabrics may include unidirectional fabrics, including pliedunidirectional fabrics wherein the fibers of adjacent unidirectionalfabric layers may be oriented to be perpendicular to one another.

Composite Materials and Resins

According to some embodiments, the ballistic-resistant composites asdescribed herein may include one or more fabrics in contact with (andwhich may be secured together using) one or more resin materials, andwhich could be thermoplastic or thermosetting resins.

In some embodiments, the ballistic composite is a rigid or semi-rigidballistic-resistant composite. As used herein, the term “rigid orsemi-rigid” include ballistic composites comprising a fabric and a resinwherein the addition of a resin decreases axial flexural deformabilityof the fabric in contact with the resin.

Greige fabrics or fabrics that are not treated with a resin system aregenerally deformable and suitable for “soft-armor” applications. Incontrast, “rigid or semi-rigid” composites are generally not deformablesuch that the shape of the composite may be readily altered by relativeflexural movement of the fibers or filaments along their axis, as thefibers or filaments are held in place by the resin.

Generally, “rigid” may be used to refer to composites made usingthermosetting resin, while “semi-rigid” may refer to composites madeusing thermoplastic resins and/or a low resin content of thermosettingresin.

In one embodiment, the dry-resin resin content of the ballisticcomposite is less than 50%. In a further embodiment, the dry-resincontent of the ballistic composite is less than 30%. In someembodiments, the dry-resin content is between 5 and 20%. In someembodiments, the dry-resin content is 8% or greater.

Resins believed to be effective include appropriate formulations ofpolymeric materials, including thermosets or thermosetting resins andthermoplastics, such as polyesters, polypropylenes, polyurethanes,polyethers, polybutadiene, polyacrylate, copolymers of ethylene,polycarbonates, ionomers, ethylene acrylic acid (EAA) copolymers,phenolics, vinyl esters, PVB phenolics, natural rubbers, syntheticrubbers (e.g. chloroprene rubbers), styrene-butadiene rubbers, etc.

In some embodiments, the resin material may additionally includeadditives to control or alter the physical or chemical properties of theresin, such as nano-particles to increase toughness of the compositesand/or fillers to reduce density and/or increase stiffness of thecomposites. In some embodiments, the resin material may also containsubstances selected so as to alter the surface properties of thecomposite, such as, for example, dyes for coloring or the like.

In some embodiments, the fibers or fabrics as described herein areprocessed to form a composite material or panel. For example, the fabricmay be fabricated into a prepreg using a film or a wet resin. Dependingon the application, the film or resin may be applied to one side of thefabric, the fabric may be totally impregnated with a resin, and/or thefilm may be worked into the fabric. In some examples, two or more layersof the fabric may be laminated together to create a multi-layer fabric.

Articles made from Ballistic-Resistant Composites

In some embodiments, the ballistic-resistant composites described hereinmay be used in armor systems.

In some embodiments, the ballistic-resistant composites are used in themanufacture of multi-threat articles that include a stab or punctureresistant component. In some embodiments, the ballistic-resistantcomposites described herein may be used with ceramics or other materialssuitable for stab-resistant product designs for spikes and edged weapons

Finished articles that may make use of the ballistic-resistantcomposites include, but are not limited to, body armor, personal armorplates and shields, commercial vehicle armor, military vehicle armor,such as spall liners, fragmentation kits, IED protection, EFPprotection, ship armor, helmets, structural armor, or generally anyapplication that uses rigid or semi-rigid ballistic and/or blastresistant composites.

The above disclosure generally describes some embodiments of the presentapplication. Further details may be obtained by reference to thefollowing specific examples. These examples are described solely for thepurpose of illustration and are not intended to limit the scope of thedisclosure. In particular, changes in form and substitution ofequivalents are contemplated as circumstances might suggest or renderexpedient. Although specific terms have been employed herein, such termsare intended in a descriptive sense and not for purposes of limitation.

EXAMPLES Example 1 Effect of DPF on Ballistic Performance of Vectran™Armor Systems

In order to do a “head-to-head” comparison of the effect of dpf in rigidarmor panels, two substantially identical Vectran® fabrics were woven,one using 2.5 dpf, Vectran HT 1500 denier (600 filament) yarn and oneusing a 5.0 dpf Vectran 1500 denier (300 filament) yarn producedcommercially for only non-ballistic applications. Both Vectran® yarnshad similar tensile strengths (of approx 25 g/denier), moduli and %elongations to break. Both were woven in the same 22×22 plain weaveconstruction using a Dornier rapier loom and both greige fabrics had adry weight of 284 gsm.

Each fabric was then laminated with the same modified thermoplasticpolyethylene ballistic film, having an areal density of 59 gsm, andpressed into ballistic test panels at various areal densities forevaluation. Based on the weight of the film applied, the ballistic testpanels all had a DRC (dry resin content) of 17.2%.

Ballistic limit (i.e. V₅₀) testing was done using .30 caliber fragmentsimulating projectiles (FSP'S) on each of the pressed test panels as perMIL-STD-662F. From the ballistic V₅₀ data generated a ballisticperformance curve was generated for both the 5.0 dpf Vectran HT basedarmor panels (FR-VEB-1055-122.0-0000 w/59 gsm ARG) and the 2.5 dpfVectran HT based armor panels (FR-VED-1055-127.0-0000 w/59 gsm ARG).This allowed for the comparison of the two armor systems across avariety of armor weights. As shown in FIG. 1, the large 5.0 dpf, 1500denier Vectran yarn tends to show better ballistics performance than the(more expensive) lower 2.5 dpf 1500 denier Vectran yarn.

For example, 56 layers of 2.5 dpf Vectran fabric pressed into anballistic plate (at an areal density 3.6 psf) had an average V₅₀performance of 2408 fps, while 56 layers of 5.0 dpf Vectran fabricpressed into an ballistic plate (at an areal density 3.6 psf) had anaverage V₅₀ performance of 2586 fps; a difference of 178 fps or 54 m/s.

Example 2 Effect of DPF on Ballistic Performance of Aramid Armor Systems

Standard Kevlar® 29, 3000 denier aramid yarn (an assembly of 1333individual 2.25 dpf yarn filaments), was compared against a lower denierper filament (1.5 dpf, 2000 filament) Kevlar, 3000 denier yarn beingintroduced by DuPont as a potential direct replacement for the Kevlar®29 yarn in ballistic applications. The 1.5 dpf Kevlar had the samenominal tenacity (26 g/denier), modulus and elongation to break as the2.25 dpf Kevlar® 29 yarn.

3000 denier Kevlar@ 29 yarn is currently used extensively in numeroushard and soft armor applications including military helmets, rigidvehicle armor systems, spall-liners and blast fragmentation blankets. Itis the yarn of choice for these applications both due to its performanceand its price point vs. lower denier and more expensive Kevlar yarns(e.g. 200, 500, 850 and 1500 denier aramid yarns). These lower denieryarns typically are made from finer dpf yarn filaments.

As will be described in greater detail below, the inventor hasdiscovered that DuPont 3000 denier has a calculated CA•dpf of 6.76 (aswill be explained below), which is believed to be the highest currentlyavailable CA•dpf for all aramids on the market.

To compare the performance of the 1.5 dpf Kevlar® yarn vs. the 2.25 dpfKevlar® 29 yarn, the 1.5 dpf Kevlar was woven into an ‘industrystandard’ 17×17, plain weave, 450 gsm fabric construction on a Dornierrapier loom. For soft armor comparison, 9 layers of this fabric was shotwith 17 grain type 1 FSP's as per MIL-STD-662F and compared to theidentical fabric constructed using 2.25 dpf Kevlar 29 yarn, as shown inFIG. 2. 9 layers of the 1.5 dpf fabric had an areal density of 0.9 psfand gave an average V₅₀ of 1481 fps. 9 layers of the standard 2.25 dpffabric had an areal density of 0.9 psf and gave an average V₅₀ of 1477fps when shot with this threat, indicating that in such a soft armorconfiguration the smaller dpf Kevlar was equivalent or potentially evenslightly better than the standard 2.25 dpf Kevlar 29 yarn.

For a hard armor comparison, both the 1.5 dpf 17×17, 3000 denier fabricand the 2.25 dpf 17×17, 3000 denier fabric were laminated with amodified thermoplastic polyethylene film 70 gsm thermoplastic ballisticfilm. Both fabrics were then cut and pressed into rigid ballistic panelsat nominal areal densities of 2.0, 3.0 and 4.0 psf. All panels had had aDRC of 13.5% by weight.

Ballistic V₅₀ testing was then performed on these rigid test panelsusing .30 caliber FSP'S as per MIL-STD-662F. Ballistic performancecurves were generated from the ballistic V₅₀ data for both the 1.5 dpf17×17, 3000 denier fabric and the 2.25 dpf 17×17, 3000 denier fabric. Asshown in FIG. 3, this allowed for a direct comparison of the ballisticperformance for the two yarn dpf's across a variety of armor weights.

As can be seen from FIG. 3, in rigid armor testing the larger 2.25 dpf,3000 denier Kevlar® 29 yarn tended to give better ballistics per unitweight than the 1.5 dpf 3000 denier Kevlar yarn. For example, 19 layersof 2.25 dpf Kevlar® 29 fabric pressed into a 2.10 psf ballistic panelhad an average V₅₀ performance of 2008 fps, while 19 layers of 1.5 dpfKevlar® 29 fabric pressed into an identical 2.10 psf ballistic panel hadan average V₅₀ performance of only 1888 fps; a difference of 120 fps or37 m/s.

Example 3 Effect of DPF on Ballistic Performance of Low DensityPolyolefin (Innegra®) Armor Systems

This example investigated whether composites using relatively large dpfyarns of relatively low-density polyolefin, aliphatic (non-aromatic)organic yarns (e.g. UHMWPE, PP, PET, Nylon/Amides) would also exhibitimproved ballistic performance compared to similar low dpf composites.

For this study high modulus polypropylene yarn (i.e. Innegra®) wasselected due to the availability of comparable Innegra® yarns ofdiffering denier per filament to test. The inventor believes that it isreasonable to assume that all aliphatic organic yarns would likely showa similar dpf related ballistic performance trend within a certain rangeof yarn filament diameters and yarn density. The range of viableballistic yarn filament diameters would be dependent on the density andphysical properties of the organic yarn selected (e.g. tensile strength,modulus, and percent elongation to break).

For this study 3000 denier 8 dpf Innegra® S HMPP yarn was comparedagainst a developmental 2800 denier 12.5 dpf Innegra® S HMPP yarn.Ideally it would have been preferable to compare identical yarn deniers(as done with Vectran® and Kevlar® above in Examples 1 and 2), but basedon the available literature and experimental testing the inventorbelieves it is reasonable to assume the slight denier difference betweenthe two Innegra yarns has minimal impact on the ballistic limit of thefinal pressed ballistic panels.

In order to do a “head-to-head” comparison the 3000 denier 8 dpf (375filament) Innegra® yarn was woven in an 11×11 plain weave constructionusing a Dornier rapier loom to give a fabric with a nominal dry weightof 302 gsm, while the 2800 denier 12.5 dpf (224 filament) Innegra® yarnwas woven in an 11.5×11.5 plain weave construction using a Dornierrapier loom to give a fabric with a nominal dry weight of 298 gsm. Thesespecific fabric constructions were chosen so as to produce as similarfabrics as possible with respect to: weight, crimp level, thickness andcover-factor. Both yarns had the same nominal tenacity of 7.8 g/den, anominal percent elongation to break of 7.75% and nominal initial modulusof 212 grams-Force/denier.

Each of these fabrics was then finished and laminated with the samemodified thermoplastic polyethylene ballistic film, having an arealdensity of 38 gsm, and pressed into ballistic test panels at variousweights for evaluation. Based on the weight of the film applied, theballistic test panels all had a DRC of approx 11%.

Ballistic V₅₀ testing was again done using .30 caliber fragmentsimulating projectiles (FSP'S) on each of the pressed test panels as perMIL-STD-662F. From the resulting ballistic V₅₀ data, a ballisticperformance curve was generated (within a limited velocity range) forboth the 8 dpf Innegra® yarn panels and the 12.5 dpf Innegra yarn panelsto allow for direct comparison. As shown in FIG. 4, the relatively large12.5 dpf HMPP yarn tended to out-perform the smaller, considerably moreexpensive 8.0 dpf HMPP yarn, for each panel weight tested.

For example, based on the equation of the lines calculated for eacharmor system in the above chart, the 12.5 dpf rigid Innegra panels wouldhave a ballistic performance limit (i.e. V₅₀) of 2248 fps (685 m/s) atan areal density of 4.0 psf, while the 8.0 dpf rigid Innegra® panelswould have a ballistic performance limit of 2106 fps (642 m/s) at thesame areal density.

The performance curves shown in FIG. 4 were assumed to be linear overthe range of weights and velocities tested. This assumption matches wellwith the experimental data but is not believed to hold true atsignificantly lower or significantly higher velocities where otherfactors may play a more significant role on the ballistic limit of thetest panels. It is believed that this 142 fps ballistic limit differencebetween the two systems is due primarily to differences in yarn dpf,with the larger dpf yarn being more efficient in dissipating the kineticenergy of the ballistic projectile in rigid composite armor.

After this work was completed another Innegra fabric was woven but thistime using an even larger specially produced 19.0 dpf (150 filament)Innegra® HMPP yarn. This was then woven in a 12.5×12.5 plain weaveconstruction using a Dornier rapier loom to give a fabric with a nominaldry weight of 320 gsm. While this fabric was slightly heavier than thepreviously woven fabrics it was still quite similar to the aboveconstructions with respect to crimp-level, thickness and cover factor.The large 19.0 dpf (150 filament) Innegra® HMPP yarn also had the samenominal tenacity of 7.8 g/den, nominal percent elongation to break of7.75% and nominal initial modulus of 212 grams-Force/denier as the yarnsused to weave the other two Innegra® HMPP fabrics.

This 19.0 dpf fabric was then finished and laminated with the samethermoplastic ballistic film having an areal density of 38 gsm, andpressed into ballistic test panels at various weights for evaluation.Based on QC testing done on this fabric, and the weight of the filmapplied, the ballistic test panels all had a DRC of approx 10.4%.

Ballistic V50 testing was again done using .30 caliber fragmentsimulating projectiles (FSP'S) on each of the test panels as perMIL-STD-662F. From the ballistic V50 data generated a ballisticperformance curve was generated (within a limited velocity range) asshown in FIG. 4A.

As evident by inspection, ballistically the larger 19.0 dpf Innegra®HMPP yarn out-performed both the mid range 12.5 dpf HMPP yarn and thesmaller more expensive 8.0 dpf HMPP yarn, at each panel weight tested.

For example, based on the equation of the lines calculated for eacharmor system in the above chart, a 4.0 psf. 19 dpf Innegra panel wouldhave a ballistic performance limit (i.e. V50) of 2342 fps (714 m/s) ascompared to 2248 fps (685 m/s) for the 12.5 dpf rigid Innegra panels ascompared to 2106 fps (642 m/s) for the 8.0 dpf rigid Innegra® panel.While it is unknown what minor impact the slightly denser fabricconstruction may have on the ballistic performance of the 19 dpf Innegrafabric, the above testing is further strong evidence that larger dpfyarn is more efficient in dissipating the kinetic energy of ballisticprojectiles in rigid composite armor.

Note that the performance curves shown in FIGS. 4 and 4A were assumed tobe linear over the range of weights and velocities tested. Thisassumption matches well with the experimental data but may not hold trueat significantly lower or hyper velocities where other factors may havea more significant influence on the ballistic limits of the test panels.

Discussion and Mathematical Models of the Ballistic Performance of LargeDPF Yarns in Rigid or Semi-Rigid Composites.

The embodiments described herein generally provide improved rigid orsemi-rigid composite armor systems (e.g. lighter, better ballisticperformance, less expensive) through the use of larger dpf highperformance yarns.

The use of larger dpf fibers or filaments for improving ballisticperformance appears counter-intuitive to what has previously beenexperimentally observed in soft armor systems. However, as shown inExamples 1, 2 and 3 above, ballistic testing done with three differenttypes of synthetic (organic) high performance yarns (Kevlar, Vectran andHMPP) suggests that rigid and semi-rigid composite armor panelsconstructed out of larger dpf yarns outperform comparable compositeballistic panels constructed out of identical or substantially identicalsmaller dpf high performance yarns.

Large dpf yarn is typically simpler and less expensive to produce on aper weight basis. Therefore, by using less expensive ‘large’ dpf yarnsin rigid or semi-rigid armor systems it may be possible to producelighter and better performing ballistic armor that is less expensivethan armor systems currently available on the market.

Without limiting the scope of the embodiments described herein, it isbelieved that the improved ballistic performance is a function of theyarn's total exposed surface area and how the individual yarn filamentsare constrained by the resin system utilized (e.g. thermoplastic orthermosetting resin). Because a low dpf yarn has significantly moreindividual yarn filaments and hence more surface area than a comparablelarge dpf yarn, a low dpf yarn itself, on a per weight basis, tends tobe in more ‘intimate contact’ with the rigid armor resin system andhence more ‘constrained’ by it.

In other words, because of the high degree of interaction between theresin and the smaller yarn's individual yarn filaments, the fibers orfilaments are believed to be less efficient at transferring thelongitudinal strain waves of a ballistic event along their length (forsmaller dpf yarns). This inefficient transfer of the longitudinal strainwaves, in conjunction with the potential reflection of these tensilewaves within the yarn, increases the total tensile load acting upon thesmaller dpf yarn at a specific point thereby prematurely breaking theyarn before the theoretical maximum amount of energy can be absorbedalong its length.

On the other hand, larger dpf yarns, with fewer filaments and lesssurface area, are theoretically less constrained by the compositearmor's resin system and hence are better be able to dissipate theenergy of a ballistic event. For example, a 2.5 dpf, 3000 denier yarn(with a specific gravity of 1.4 g/cm³) has 1200 individual yarnfilaments and hence, one linear meter of this yarn would have atheoretical total surface area of 599.2 cm². In comparison, one linearmeter of an identical 3000 denier yarn, at 5.0 dpf would have 600 yarnfilaments and would consequently have only a theoretical surface area of423.7 cm². This corresponds to a 30% reduction in total yarn surfacearea as compared to the smaller dpf yarn.

In some cases, a good ballistic fiber should have the following keyproperties: high strength, high strain to failure, high elastic modulusand low density. Mathematically, a yarn's theoretical ballisticperformance can be modeled using Equation 1 as follows:U _(y)=[(Y·ε _(f)/2ρ)·√{square root over (E/ρ)}] ^(1/3)=[(Y·ε_(f)/2ρ)·c] ^(1/3)  (1)Where:

U_(y)=the theoretical ballistic performance of an ‘unconstrained’ yarn

Y=the yield strength of the yarn

ε_(f)=the yarn's % strain to failure

E=the yarn's elastic modulus

ρ=the density of the yarn

c=the sound speed of the yarn

(See Phillip M. Cunniff, Margaret A. Auerbach, High Performance “M5”fiber for Ballistics)

Equation 1 has shown good correlation to actual experimental ballistictesting.

The inventor believes that Equation 1 would also generally hold true inrigid and semi-rigid composite armor systems. However, the inventor hasdiscovered that the effect of the resin matrix should also be taken intoconsideration.

Assuming that the organic ballistic yarn does the vast majority of thework in stopping a ballistic projectile within a composite armor, andignoring transverse wave effects (which may in fact be significant) theinventor has developed Equation 2 which is believed to summarize thetheoretical ballistic performance of a yarn within a resin matrix:

$\begin{matrix}{U_{yRM} = \left\lbrack {{\left( {{Y \cdot {ɛ_{f}/2}}\rho_{yarn}} \right) \cdot \frac{1}{2}}\left( {{\left( {2 - a} \right)\sqrt{E_{yarn}/\rho_{yarn}}} + {a\sqrt{E_{resin}/\rho_{resin}}}} \right)} \right\rbrack^{1/3}} & (2)\end{matrix}$Where:

U_(yRM)=the theoretical ballistic performance of a ‘constrained yarn’within a resin matrix.

a=the % interaction between the resin matrix and the ballistic yarn inthe rigid composite armor.

As can be seen from Equation 2, the yarn's ballistic performance is afunction of both its own elastic modulus and density and the elasticmodulus and density of the resin matrix itself. This reflects that thespeed of sound through an anisotropic composite material will be someaverage of both the yarn's sound speed and the resin's sound speed.

Further, given the extremely high elastic moduli of ballistic yarns(e.g. ˜75 GPa for Kevlar 29) relative to most standard composite resinmatrices (0.2 GPa for LDPE) the inventor interprets Equation 2 toindicate that:

-   -   The resin matrix typically has a negative impact on the        theoretical ballistic performance of the ‘constrained’ yarn; and    -   The ‘negative impact’ of the resin matrix can be minimized by        reducing the % interaction between the resin matrix and the        ballistic yarn in the composite armor.

The “% interaction” between the resin matrix and the yarn is generallydependent both on the level of resin encapsulation and on themicroscopic mechanical/chemical interaction between the yarn's surfaceand the resin itself. For example, if a composite resin system ‘binds’the yarn bundle but fails to individually encapsulate each of the yarn'sthousands of individual yarn filaments, then the yarn may be considerednot to be substantially encapsulated, and the degree of interactionrelatively low. Conversely, if a strong chemical bond exists between theyarn's surface and the resin, as opposed to simply a mechanical bond,then the relative “% interaction” will tend to be greater.

% Interaction thus generally measures how well an acoustic sound wavemoving through two dissimilar materials in close contact with each otherwould equalize between one another (e.g. between the yarn and theresin).

Equation 2 therefore provides a conceptual validation that the ballisticperformance of yarn within composite armor can be improved by increasingthe dpf the ballistic yarn's filaments, thereby decreasing the yarn'ssurface area and reducing the relative degree of interaction betweenresin matrix and the yarn.

This model also agrees with experimental results in aramid compositearmors with respect to dry resin content (DRC). For aramid compositearmors, typically the ballistic performance of the panel (i.e. its V50ballistic limit) is inversely proportional to the DRC of the armor'sresin system—i.e. the lower the DRC of the panel, the higher the panelsV50 ballistic limit until a ‘critical point’ is reached where theballistic panels simply break apart or delaminate excessively whenimpacted by a projectile due to insufficient resin.

It is also of note that inorganic ballistic glass roving (also widelyused in composite armor systems) does not show this large dpf effect incomposite armor. In fact, the reverse has been experimentally provenwhere smaller denier per filament glass yarns outperform larger dpfyarns in rigid pressed ballistic panels when impacted by eitherdeformable or non-deformable ballistic rounds.

One possible reason for this difference is that inorganic glass yarnsfail and dissipate the energy of a ballistic event in a significantlydifferent manner than do organic high performance yarns as describedherein. Accordingly, ballistic glass based armors also typically performbetter the higher the DRC of the composite armor until the parasiticweight of the ‘non ballistic’ resin adversely impacts the V50performance of the ballistic panel. This suggests that substantialencapsulation and bonding of the resin system with ballistic glass yarnsis beneficial to performance, not detrimental.

The fact that the ballistic yarns in a composite ballistic panel areheld ‘rigidly’ in place is another potential reason why large dpforganic yarns are believed to perform better in hard armor systems thanin soft armor systems. Since the yarns in hard armor (e.g. rigid and/orsemi-rigid armor) are fixed in place, they are not as easily pushedaside by a ballistic projectile impacting the composite armor. Thismeans that the projectile is ‘forced’ to impact and break yarns (e.g.via tensile yarn failure), which dissipates significantly more energythan if the projectile were to largely ‘push aside’ the yarns within thevarious layers of the composite armor thus impacting and breaking only aminimum number of yarns.

However, in soft armor, where yarn and filaments are relativelyunconstrained and free to move, large dpf yarn filaments wouldtheoretically be more prone to being ‘pushed aside’ by a projectile thancomparable smaller dpf yarn filaments.

Example 4 Further Vectran dpf Testing

To attempt to better understand the impact of dpf in rigid armor panels,determine optimum or commercially desirable yarn dpf for rigid armorpanels, and determine a practical dpf range for high performance yarnsin rigid armor panels, further testing was performed.

Two identical Vectran® fabrics were again woven, however this time using5 dpf Vectran HT 3000 den yarn and a developmental very large 15 dpf,3000 denier Vectran HT yarn specifically requested by Barrday Inc. forthis research.

The 5 dpf 3000 denier Vectran HT yarn consisted of 600 individual yarnfilaments bundled together and the 15 dpf 3000 denier Vectran HT yarnconsisted of 200 individual yarn filaments bundled together. BothVectran® yarns had the same nominal tenacity (23.5 cN/dtex), moduli and% elongation to break at 3.7%. Both were woven in the same 17×17 plainweave construction using a Dornier rapier loom and both greige fabricshad a dry weight of 465 gsm.

Each of the fabrics was then laminated with the same modifiedpolyethylene thermoplastic ballistic film, having an areal density of 70gsm, and pressed into ballistic test panels at various areal densitiesfor evaluation. Based on the weight of the film applied, the ballistictest panels all had a DRC of 13.1%.

Ballistic limit (i.e. V50) testing was again done using .30 caliberfragment simulating projectiles (FSP'S) on each of the test panels madeas per MIL-STD-662F. From the ballistic V50 data generated a ballisticperformance curve was generated for both the 5.0 dpf Vectran HT basedarmor panels (FR-VEB-1013-127.0-1139) and the 15 dpf Vectran HT basedarmor panels (FR-VEF-1013-127.0-1139). This allowed for the comparisonof the two armor systems across a variety of armor weights.

As can be seen from FIG. 5, the exceptionally large 15.0 dpf, 3000denier Vectran yarn (with a CA•dpf factor of 41.16, as will be describedbelow) gave equivalent or even slightly better ballistics performancethan the more expensive 5.0 dpf 3000 denier Vectran yarn.

For example, 28 layers of 5.0 dpf Vectran fabric pressed into anballistic plate at an areal density 15.1 kg/m2, had an average V50performance of 664 m/s, while 28 layers of the 15.0 dpf Vectran fabricpressed into an ballistic plate at the same areal density had an averageV50 performance of 673 m/s, a difference of 8.5 m/s or 28 fps.

This data was then used to generate the FIG. 6, which models atheoretical ballistic limit performance curve of 3.0 psf Vectran HTcomposite armor panels, constructed from different dpf Vectran yarnsusing a second order polynomial curve.

As can be seen from this theoretical second order polynomial curve, itappears the ballistic performance of a composite armor panel will tendto increase as the dpf is increased until an optimal dpf for the yarn isreached, after which the performance will tend to decrease as dpf isincreased. The dpf will be yarn specific and is believed to be afunction of the density of the yarn, along with other factors such asits tenacity, modulus and percent elongation to break.

In an attempt to model the impact of dpf across a wide variety of highperformance ballistic yarns (i.e. aramids, HMPP, UHMWPE,Polyester-polyarylate (e.g. Vectran®), PBO, modified-aramids etc.) andcarbon yarn, the data from the above Vectran testing was analyzed incomparison with commercially available dpf's and densities ofhigh-performance yarns currently used in hard armor systems.

From this analysis, the inventor discovered that the commercially viabledpf range of high-performance yarns is primarily a function of theyarn's/polymer's density, with commercially available yarn dpf's beinginversely proportional to base polymer's density cubed.

This is believed to make sense theoretically, because the lower thepolymer's specific gravity, the larger the volume of yarn required perunit weight, and because density has been shown experimentally to be akey factor influencing the ballistic performance of high performanceyarns.

Based on these findings, the inventor developed the following concept ofa “Composite-Armor dpf factor” (CA•dpf), where CA•dpf is equal to theratio of a yarn's individual yarn filament denier (dpf) to the inverseof the yarn's density cubed, which can be simplified to the product of(yarn dpf) times (yarn density^3), as shown in Equation 3:

$\begin{matrix}{{{CA} \cdot {dpf}_{factor}} = {\frac{{dpf}_{yarn}}{\left( \frac{1}{\left( {density}_{yarn} \right)^{3}} \right)} = {{dpf}_{yarn} \times \left( {density}_{yarn} \right)^{3}}}} & (3)\end{matrix}$

Based on available literature, some rigid and semi-rigid composite armorpanels were analyzed and were discovered to have CA•dpfs of between 0.9to 6.86, with the majority having a CA•dpf of between 4.5 to 6.7. Forexample, currently the largest CA•dpf yarn used in hard armor systems(while only a developmental level) is Vectran HT 2.5 dpf yarn with aspecific gravity 1.40. This dpf, density combination results in a CA•dpfof 6.86.

According to some embodiments, the composites described herein includeyarns which have a CA•dpf of greater than or equal to 7.0. According toother embodiments, the composites described herein include yarns whichhave a CA•dpf of greater than or equal to 15. According to otherembodiments, the composites described herein include yarns which have aCA•dpf between 25 and 35. According to yet other embodiments, thecomposites described herein include yarns which have a CA•dpf of between27 and 28.

According to some embodiments, the composites described herein mayinclude yarns which have a CA•dpf of less than or equal to 85.

In some embodiments, a CA•dpf of 85 is proposed as an upper practicallimit. However, such an upper limit has not been experimentallyverified, and may be higher depending on whether the ballistic limitperformance curve relating to dpf tends to be polynomial or logarithmicin nature. In particular, if the ballistic performance curve islogarithmic, higher dpf may be beneficial as generally shown in FIG. 7(for example, polyester polyarylate (Vectran) with a dpf of 35 or moremay provide good ballistic performance).

Based on experimental testing and using the second order polynomialmodel given above, the concept of the CA•dpf factor can be used topredict a theoretical commercially desirable dpf for any highperformance yarn in a composite armor system (generally subject to theprovision that the yarn's filaments can be produced at these large dpf'swith equivalent tenacity, % elongation to break and tensile modulus tothe smaller dpf yarns, which may be challenging in practice due to theyarn production and drawing requirements).

TABLE 1 Calculated CA-dpf Factors of Potential Ballistic Yarns HighestDensity Commercially CA-dpf Predicted (specific Available DPF usedFACTOR (for Commercially Yarn type gravity) in composite armor AvailableDPF) Desirable dpf Para Aramid (Kevlar 1.44 2.25 6.72 9.35 Twaron etc)Para Aramid-Twaron 1.44 0.84 2.51 9.35 micro filament Modified Para 1.471.1 3.49 8.80 aramid (AuTex HT) Polyester 1.40 2.5 6.86 10.20polyarylate (Vectran) HMPP (Innegra)** 0.84 8.0 4.74 47.04 HMPP(Innegra) 0.91 8.0 6.03 37.00 literature UHMWPE (Spectra 0.97 5.4 4.9330.55 Dyneema) UHMWPE 0.97 1 0.91 30.55 (Dyneema- microfilament) PBO(Zylon HS) 1.54 1.5 5.48 7.65 PBO (Zylon HM) 1.56 1.5 5.69 7.35 M5fiber* 1.70 1 4.91 5.65 Carbon 1.76 0.6 3.27 5.10 Nylon 1.14 n/a n/a18.80 Polyester 1.38 n/a n/a 10.50 *dpf is an estimation not reported inliterature **Measured density of HMPP fiber within a composite n/a isnot available since not widely used in composite armor

For example, based on the Vectran data presented above, a commerciallydesirable dpf for Vectran yarn is about 10.2 dpf, while a commerciallydesirable dpf for Kevlar yarn (which is slightly more dense, with aspecific gravity of 1.44) is about 9.35 dpf. For carbon yarn (which isrelatively quite dense) a commercially desirable dpf is 5.1 dpf. Itshould again be noted that this commercially desirable dpf is solelybased on density comparisons between yarns, and that tenacity, modulus,and % elongation to break will also be factors in determining this.

Turning now to Table 2, listed therein are CA•dpf factors for some ofthe example ballistic fabrics as described herein.

TABLE 2 Calculated CA-dpf Factors for Ballistic Examples CA-dpf Factorof Yarn in Yarn type Density Yarn dpf Composite Para Aramid (KevlarTwaron etc) 1.44 1.5 4.48 Para Aramid (Kevlar Twaron etc) 1.44 2.25 6.72Polyester polyarylate (Vectran) 1.4 2.5 6.86 Polyester polyarylate(Vectran) 1.4 5 13.72 Polyester polyarylate (Vectran) 1.4 15 41.16 HMPP(Innegra) fiber in 0.84 8 4.74 composites** HMPP (Innegra) fiber in 0.8412.5 7.41 composites** HMPP (Innegra) fiber in 0.84 20 11.85composites** **Measured density of HMPP fiber within a composite

While the above description provides examples of one or more ballisticresistant composites, it will be appreciated that other ballisticresistant composites may be within the scope of the present descriptionas interpreted by one of skill in the art.

The invention claimed is:
 1. A rigid ballistic-resistant composite,comprising: a) a plurality of yarns arranged into a fabric, the yarnshaving a “Composite-Armor dpf factor” (CA•dpffactor) selected to provideimproved ballistic performance; and b) a resin in contact with thefabric to form a rigid composite panel in which the yarns of the fabricare held in place by the resin, wherein CA•dpffactor is determinedaccording to the following equation:${{{CA} \cdot {dpf}_{factor}} = {\frac{{dpf}_{yarn}}{\left( \frac{1}{\left( {S.G._{yarn}} \right)^{3}} \right)} = {{dpf}_{yarn} \times \left( {S.G._{yarn}} \right)^{3}}}},$wherein dpfyarn is a denier per filament of the yarns, wherein S.G.yarnis a specific gravity of the yarns, and wherein the yarns have aCA•dpffactor of less than 85, and include poly-para-phenyleneterephthalamide fibers having a CA•dpffactor of greater than 6.72. 2.The rigid ballistic-resistant composite of claim 1, wherein the yarnshave a CA•dpf_(factor) between 6.75 and 9.35.
 3. The rigidballistic-resistant composite of claim 1, wherein the yarns comprisepoly-para-phenylene terephthalamide fibers having a dpf_(yarn) ofgreater than 2.25.
 4. The rigid ballistic-resistant composite of claim3, wherein the poly-para-phenylene terephthalamide fibers have adpf_(yarn) between 2.25 and 9.5.
 5. The rigid ballistic-resistantcomposite of claim 1, wherein the resin is a thermosetting resin.
 6. Therigid ballistic-resistant composite of claim 1, wherein the resin is athermoplastic resin.
 7. The rigid ballistic-resistant composite of claim1, wherein the resin is selected from the group consisting of:polyesters; polypropylenes; polyurethanes; polyethers; polybutadiene;polyacrylate; copolymers of ethylene; polycarbonates; ionomers; ethyleneacrylic acid (EAA); copolymers; phenolics; vinyl esters; PVB phenolics;natural rubbers; synthetic rubbers; polyethylene; and styrene-butadienerubbers.
 8. The rigid ballistic-resistant composite of claim 1, whereinthe yarns comprise organic high-performance fibers.
 9. The rigidballistic-resistant composite of claim 1, wherein the yarns compriseindustrial fibers.
 10. A protective material comprising the rigidballistic-resistant composite as claimed in claim 1, wherein theprotective material is selected from the group consisting of: bodyarmor; personal armor plates; personal armor shields; commercial vehiclearmor; military vehicle armor; lightweight aircraft armor; ship armor;helmets; and structural armor.
 11. The rigid ballistic-resistantcomposite of claim 1, wherein the yarns have a CA•dpf_(factor) of about9.35.
 12. A rigid ballistic-resistant composite, comprising: a) a resin;and b) a plurality of yarns held in place by the resin, wherein theyarns have a “Composite-Armor dpf factor” (CA•dpf_(factor)) determinedaccording to${{{CA} \cdot {dpf}_{factor}} = {\frac{{dpf}_{yarn}}{\left( \frac{1}{\left( {S.G._{yarn}} \right)^{3}} \right)} = {{dpf}_{yarn} \times \left( {S.G._{yarn}} \right)^{3}}}},$wherein dpf_(yarn) is a denier per filament of the yarns, whereinS.G.density_(yarn) is a specific gravity of the yarns, and wherein theyarns include poly-para-phenylene terephthalamide fibers having aCA•dpf_(factor) of greater than 6.72.
 13. The rigid ballistic-resistantcomposite of claim 12, wherein the yarns comprise poly-para-phenyleneterephthalamide fibers having a dpf_(yarn) of greater than 2.25.
 14. Therigid ballistic-resistant composite of claim 13, wherein thepoly-para-phenylene terephthalamide fibers have a dpf_(yarn) between2.25 and 9.5.
 15. The rigid ballistic-resistant composite of claim 12,wherein the yarns have a CA•dpf_(factor) of about 9.35.